At the start of 2016 I used to get a downstream speedtest result from speedof.me of >7.7 Mbps, and until fairly recently my combined upload speed was > 1.0 Mbps.
The upload speed loss is a complete mystery, in that the DSL numbers don't seem to have changed. Neither can one tester be blamed as all show a decrease, even though they don't agree with one another. I haven't examined the history of Firebrick software upgrades to see if there's a possibility of the Firebrick's upload aggregation having become less optimal.
The download speed is due to sync speed reductions of a few hundred k across all three lines, and the noise margins have grown less be around 1 dB. It's possible that the attenuation has worsened slightly, I'd have to recheck this.